There is emerging consensus that a pro-inflammatory condition contributes to the vaso-occlusive complications of sickle cell disease (SCD). We evaluated the potential value of inflammatory mediators as early markers of severity of painful vaso-occlusive crises (VOC) in SCD. We assayed the plasma levels of cytokines, soluble vascular cell adhesion molecule-1, acute phase proteins, secretory phospholipase and standard hematologic indices.